PIANO FORTE: Even amid the multimedia spectacle that was Ermenegildo Zegna’s 100th anniversary bash at the Triennale Design Museum Monday night, composer Michael Nyman’s piano performance stood out as a treat. It included “The Promise,” the theme he composed for “The Piano.” Early that day, Nyman’s music was used in the Z Zegna portion of the runway show. He also made a film of a Zegna mill that played on a continuous loop in the exhibition. “And I look great in their clothes,” he said, vamping in a black suit. Among his other projects, a film called “Nyman With the Movie Camera” is headed for the Toronto Film Festival, and he’s been tapped to receive a Lucie Photography Award.